You know what we need from Hollywood? More depressing movies about trendy causes, injected with plotlines designed to make you sad about driving your car and eating meat. So says the U.N., anyway: It wants Hollywood to make movies with global-warming plots. And instead of “U.N.,” perhaps we should say “the secretary general, angling to set up some meetings and get some autographs. For his kids, you understand.” Said the L.A. Times last month:

The beleaguered multi-national agency, fresh from a disappointing round of climate negotiations in Cancun, wants something more concrete: actual story lines in movies, television and social media drawing attention to the dangers of global warming.

The push comes at a time when public concern over climate change has plummeted in the polls and Congress has rejected federal legislation to curb greenhouse gas emissions.

“Usually I speak to prime ministers and presidents, but that has its limits,” said U.N. Secretary-General Ban Ki-moon, who arrived in Los Angeles . . . for a high-profile outreach effort. “Movie producers, directors, actors — they have global reach.”

Well, so do the plague and the jet stream, but that doesn’t mean we want them to tell us how to live, either. The only way you’ll get a “story line” about climate change in “social media” is if Charlie Sheen changes his tagline from “#winning” to “#warming,” and even then people will think he dropped a cigarette and set his pants on fire.

As for movies and TV: Make all your products with natural light and hand-cranked cameras. Better yet: Stop making movies. They consume tremendous amounts of resources, and we don’t mean the catering bill for a Michael Moore documentary. The sets to build. The location shoots. The flights to Cannes. All those metal statuettes produced by industrial activity. A pat on the back would do, and it’s sustainable! Then there’s the cost of heating and cooling the theaters themselves, the electricity needed to project the movies, the ruinous consequences of factory farms that produce the pig snouts for the hotdogs, the effect on the ethanol industry of diverting precious renewables to something as non-essential as popcorn, the petroleum byproducts generated by the manufacture of popcorn topping. Gaia would be happier if Hollywood just e-mailed everyone the script, and we could all read it out loud at home.

On the other hand: What is Ban Ki Moon talking about? Hollywood has never been shy to use the Jaws of Life to crack open a plot and stuff it with trendy miseries. The Seventies were famous for wrist-slitting dystopias, usually based on the twin fears of pollution and overpopulation. Silent Running concerned some spaceships parked off Jupiter with the last of the planet’s trees and shrubs, tended over by a goggle-eyed agronomist (Bruce Dern). When the order was given to blow up the trees — with nuclear weapons! you fiends! — and bring the ships back home, he killed the crew and puttered around the forest in a holy-hippie robe with Joan Baez on the soundtrack until all the plants got sad and died. This movie was directly responsible for the creation of the EPA, some say; Nixon wept.

Actually, no. It had no more effect than Planet of the Apes had on the START treaty. Speaking of Charlton Heston, his classic Soylent Green featured a world in which mankind survived by eating minced remains of the recent dead, presumably with flavorings to mask the taste of Uncle Eddie. Movies like this had an effect, all right: They made people want to see something like Star Wars, please, just the way Woodstock made some grumble that the draft needed a whoooole lot fewer deferments, if you get my drift.

So what kind of movies do they want? Inconvenient Truth: Sustainably Generated Electric Boogaloo? A remake of South Pacific where everyone’s up to their knees in the drink because the island’s submerged? Don’t think you’ll get an updated version of The China Syndrome in which a minor reactor incident is solved in twelve minutes by well-trained technicians but the director of the reactor locks himself in the control room and demands the media let him give a stirring, impassioned plea on behalf of modern technology.

Yeah, call that one The Nippon Syndrome, you say. You do? Man, you’re reading the wrong magazine. Anyway, the Japanese situation would make for a gripping movie, if told with respect for the facts. But no. We’ll get something earnest and pedantic, or another big-budget slab of dramatic imbecility like The Day After Tomorrow or Waterworld. Or another deadpan alien warning us about our wicked, wicked eco-sins (The Day the Earth Stood Still). Or another movie about how deforestation leads to vicious attacks on mankind by animals deprived of their food (Yogi Bear).

The Japanese tragedy underscored an ancient fact: The very earth we’re trying to save with hemp shopping bags and bird-mincing windmills can kill us wholesale with a shrug. Altering the behavior of such a beast with electric cars and curly light bulbs is a daunting task. But Hollywood can stir the conscience of the world now and then. In five years a brilliant, haunting film will depict the sufferings of the Libyan people, how they waited for help that never came. It’ll probably be a foreign movie. Unless Angelina gets attached to the project.